Apparatus for measuring the thickness of the material of articles, such as tubes, etc.



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June 13, 1950 B. LJUNGSTRM ETAL 2,511,276

APPARATUS EoR MEAsuRING THE THIcKNEss oF TEE MATERIAL oF ARTICLES, sucH As TUBES, ETc

Filed Feb'. 2, 1944 6 Sheets-Sheet 2 g a /C/A June 13, 1950 B. LJUNGSTRM ETAL 2,511,276

APPARATUS FOR MEASURTNG THE THICKNEss oF THE MATERIAL 0F ARTICLES, SUCH AS TUBES, ETC

6 Sheets-Sheet 3 Filed Fellc 2, 1944 oow Q t n L, f W L 1 mix. ww. m. a s

June 13, 1950 B. JuNGsTRM ETAL 2,511,276

' APPARATUS FOR MEASURING THE THICKNESS 0F THE MATERIAL OF ARTICLES, SUCH AS TUBES, ETC

-6 Sheets-Sheet '4 Filed Feb. 2, 1944 La/1&5 $022/ In U June 13, 1950 B. LJUNGSTRM ETAL 2,511,276

APPARATUS FOR MEASURING THE THICKNESS OF THE MATERIAL OF ARTICLES, SUCH AS TUBES, ETC Filed Feb. 2, 1944 6 Sheets-Sheet 5 il ,y a

4a .23 J0 38 i/3.9444 33M .ai A if I Z 22:0 ezvozus jLl/ilom June 13, 195o B. LJUN'GSTRM Em. 2,511,216

APPARATUS FOR MEASURING THE THICKNESS 0F THE MATERIAL 0F ARTICLES, SUCH AS TUBES, ETC

Filed Feb. 2, 1944 -6 Sheets-Sheet '6 i 46 W10 4/ E 42 4/ al .w40 m, 9 Maa 'lm "(4" I l 42 4 j;\

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5' l j? 2-a A 33 jL un @if 01;@ .JFLa/olv' 'w W Ilm/162i 019145 Patented June 13, 1950 APPARATUS Fon MEASUEING THE THICK- NEss oF THE MATERIAL or ARTICLES, sUoH As TUBES, ETC.

Birger Ljungstrm, Stockholm, and Gustaf Hjalmar Larsson, Alsten, near Stockholm, Sweden, assignors to See Fabriks Aktiebolag, Sandvken, Sweden, a corporation of Sweden Application February 2, 1944, Serial No. 520,796

. 1n Sweden February 12, 1943 6- Claims.

The measuring of the thickness of the material of articles at diicultly accessible points, for instance at different pointsof a tube, offerscom'- paratively great diculties. 1n certain cases, this measuring or control is, however, of Very material importance, particularly in case of tubes having varying wall thickness, for instance those which are conical towards both ends outwardly as well as inwardly or are provided with conical portions or with swells on theY insides or the outsides.

Said difficulties are eliminated in a comparatively simpIe manner Aby using an apparatus constructed according to the present invention which apparatus Yis suitable also for measuring the thickness of other articles', for instance plates,

particularly when it is a question of controlling the thickness at points situated at comparatively great distances from the limiting edges of the articles, in which case the apparatus hitherto used for this purpose have proved to be more or less unsuitable.

A characteristic feature of the vapparatus under consideration consists therein that it is provided with at least one pair of feeling members located vopposite each other and on opposite sides of the article, one of whic'hmem'bers is supported by a tautly stretched wire or rod and the other by the frame of the apparatus or 'by a part rigidly secured to the fixing points of the wire or rod, the feeling members, the wire or rod and its Xing points being so Aarranged as to permit relative movement between the article and the feeling members Afor the `ypurpose of rneasuri'r-igthe thick- :ness of the material along the article in its entirety or the portion thereof intended to be 'measnred,l the thickness at the point of measurement being indicated by measuring or indicating instruments operatively connected to the feeling members.

According Vto -a simple embodiment vof the allparatus, the support 'thereof may consist of an elongated frame er the like', the ends of .which are provided with Tlining terminals for the Wire or rod which together with the support is `lmovable relatively tothe article, or vice versa. However, such an embodiment practically is suitable only Jfor measuring the thickness of the material of Iarticles having cornparatively small dimensions. Other embodiments, which are more *particularly .delinea below, are suitable for measuring the fthiclrnesscf the materialof 'anticles having larger dimensions. The -floor,,v,vall or other apart of the building, wherein measurement takes place, may, in certain cases, form an integra-nt part of appav'ratas intended for the measuring -of articles hav- ;ing particularly large dimensions. Y

According to certain embodiments, the adjustment of the feelers takes place automatically, and similarly the instrument or instruments indicate the adjustments automatically and therebythe thickness of the material at the point of measurement. The measuring may be carried out with the use of solely mechanical means or a combination of mechanical and electric means. If solely mechanical means are used, the feelers may be carried by two taut wires or straight rods and be connected to the measuring or indicating instrument via suitable motion transmission devices. In both cases the article, the thickness of the material of which is to be measured, is carried by a movable support which is adapted to carry said article parallel to the wires, so that they extend on opposite sides not only beyond the points to be measured but also beyond the article in its limit positions.

When a combination of mechanical and electric means is used, one of thev feelers may consist of an electric contact device and the opposite feel- 'er may 4cons-ist oran adjustable. measuring instru'- ment. According to the last-mentioned embodiment, the contact device and the measuring instrument are so electrically interconnected across a source of current that the circuit is closed when the point of measurement yis touched from two opposite directions by the contact device and the measuring instrument, to cause a sound or light signal to be brought about Athus indicating that the thickness of the material has been measured.

In the current-conducting .connection between the measuring instrument and the contact device an 'electromagnet may be directly or Yindirectly ,ineluded to serve as a magnetic `brake to brake or lock the measuring instrument, so .that the ad.- justing movement of the latter automatically interrupted and the reading of the CQITect measuring value is thereby ensured. A comparatively feeble contact current may be used Afor closing, across an electromagnet, the contact `for a magnetic brake actuated by the light current.

Besides, the modification of the intended apparatus maybe varied in many ways lWith-in the scope of the invention which, therefore, is not limited to those examples which are .described in the following with reference to the accompanying drawings.

Figure l is an elevational view partly .in section of a simple apparatus laccording to the invention. Figure 2 is an end view, .as viewed from the left in Figure 1. Figure 3 is a side View of a por.- tion of the apparatus according to an .embodiment using only mechanical means. Figure .4 shows, on a reducedscale and diagrammatically,

the last-mentioned embodiment in its entirety. Figure is a side view of an apparatus according to Figure 3. Figure 6 is a cross-section of the apparatus according to Figure 5. Figures 7a, 7b are side views and Figures 8a, 8b plan Views respectively of the apparatus according to an embodiment particularly intended for the measurement or control of the thickness of the material of comparatively long tubes. Figure 9 is, on a larger scale, a section along line S-- of- Figure 7a. Figures 10 and 11 show details of the embodiment according to Fgures 7a, 7b and 8a, 8b. Figure 12 shows diagrammatically details of a modiiication of the apparatus according to Figures 7a, 7b, and 8d, 8b. Figure 13 is on a larger scale, a section along line I3-I3 of Figure 12.

According to Figures 1 and 2, the apparatus consists of an elongated frame I or the like, the ends of which are provided with brackets or holders 2 and 3, which form tying points, for a supporting member in the form of a taut wire or rod 4. One end of the wire or the rod has an abutment 5 which bears on the bracket 2 when a nut, screwed onto the other end of thewire or the rod, is set against the other bracket 3, for the purpose of stretching the wire or the rod to a suitable degree. The bracket 2 is in the form of a fork (see Figure 2), so that the wire or rod may be conveniently disconnected lrom the bracket so that a tube a may be introduced over the wire, as shown in Figure 1. Applied to the wire or the rod is a feeler 6, adapted to cooperate with the inside of the tube a, if it is intended to control the thickness of the material of a tube. The thickness of plates and the like may, of course, also be controlled by the use of the apparatus, in which case the feeler B has for its duty to cooperate with one side of the plate, etc. Opposite the feeler 6 there is provided another feeler 1, carried by the frame I and adjustably guided in the latter towards and away from the firstmentioned feeler. The feeler 'I is connected to an indicating instrument 8 carried by the frame, said instrument operating in response to displacement of the feeler 1. The starting position of the feeler I may be regulated in a suitable manner, e. g. by means of an adjusting nut 9, screwed onto a guide sleeve I!) or the like, designed for the feeler or the connections thereof with the indicating instrument, and carried by the frame.

For the purpose of electrically controlling the measuring operation there may be connected to the Wire or the rod 4 or to the frame I, an electric conductor II, which across a current source I2 and a glow-lamp I3, is associated with the indicating instrument 8 and thereby also with the feeler 1. If desired, the current source and the glow lamp may be replaced by a pocket lamp (not shown). In the case of electric control, the feeler 'I and the indicating instrument 8 are electrically insulated from the frame, which may also be the case as regards the outside of the wire or the rod 4, so that unintentional contact-closing relatively to the article, the thickness of the material of Which is to be measured, is prevented.

In the use of the apparatus, the wire is stretched to such an extent that the feelers 6 and 1 will directly contact each other, while at the same time the indicating instrument indicates zero position, whereby the indicating instrument is also utilized for indicating the intended tension of the Wire. Thereafter, relative movement between the article and the apparatus is brought about-either by moving this 1atter or by moving the articleso that diierent portions of the article, e. g. the tube a, are introduced between the feelers 6 and 1. As a result, the feeler 1 is displaced and actuates the indicating instrument which directly indicates the thickness of the material at the point of measurement in question. This apparently also takes place in case the measurement is carried out without electric control. If the apparatus, for the purpose of obtaining as great an accuracy as possible, is also provided with an electric controlling device, the circuit comprising the lead Il is closed, inasmuch as contact is established between the feelers across the tube a which, in this case, is supposed to consist of current-conducting material. On account of the closing, the lamp I3 or the before-mentioned pocket lamp, ignites, whereby it is indicated that proper measuring conditions are present. After the measuring operation a zero indication by the indicating instrument shows that the position of the wire or rod has not been altered during measuring. f

The apparatus may be resiliently suspendedvertically or horizontally-or be carried by levers loaded by counterweights. However, there is nothing to prevent the apparatus, particularly in the case of small dimensions, from being operated entirely by hand. Of course, indicating instruments of different kinds may be used and, if desired, be replaced by a simple lever pointer cooperating with a graduate sector. Yet, under all circumstances it is assumed that the instrument or indicating device employed has a high sensibility.

According to the embodiment shown in Figures 3 and 4, two strong steel wires 4 are xed parallel to each other under tension in a suitable support which may be designed in many different ways, and, therefore, is not shown in the drawings. Each wire is, at one end, conveniently detachably secured to a stationary wire anchoring means I4 (see Figure 4) and at its other end connected to a hydraulically operable piston I5 or the like. The cylinders of the two pistons may communicate hydraulically so that the wires may be stretched equally and to the desired degree. Fastened to the wires are clamp sleeves I6 or the like which pivotally carry two mutually opposite, swingable feelers I'I having suitably the shape shown in the drawings. These feelers are pivotally connected to sleeves I8 which are slidable on the wires 4. The sleeves I8 are provided with arms I 9 cooperating with the actuating members 2l of an indicator 20, which members tend to assume certain starting positions corresponding to the zero position of the indicator, in which 1atter position the feelers contact each other. The indicator may be carried by links 22 in a parallelogram like manner (see Figure 3).

It is to be noted that the upper member 2| of the indicator 20 (Fig. 3) is a reciprocal member, spring-actuated in the direction toward the right. Owing to said spring-actuation and to Vthe fact that the indicator 20 is supported by the links 22 in the manner shown in the drawing, the arms I9 are acted upon so as to adjust the sleeves I8 in a position for normally closing the feelers I'I. When said feelers are moved apart from each other by the Wall of the tube a, the upper arm I9 is pressed against the upper member 2l and at the same time the lower arm ..5 119 actuates fthe lower member 2| in the opposite direction las 'according to this embodiment fof the invention the lower member 2l is not a reciprocal member but constructed as a iinger or hook projecting from the casing of the indicator Yand catching the lower arm I9.'

The article, the thickness of the lwall of which is to be measured, is introduced between .the feelers Il which hence are operated and displace the sleeves I8, the consequence of Awhich is that the arms I9 Aof the sleeves lactuate the indicator 20, the deflection of the pointer of which directly indicates the thickness of the material at the point of measurement.

` In case' the article is'in the form of a tube a, Vas indicated in the drawings, this is introduced over .one of thewires 4. If the article, e. g. the tube, is comparatively long, the pairs of .feelers as well as the indicator are preferably doubled so that'the thickness of the material can be Kmeasured from each end lof the tube, considered in the direction towards the centre, which embodiment is suggested in Figure e. in which 4the positions of the feelers are indicated by the marking lines designated by b. Besides, the 'number of the wires or rods may, of course, be varied.

A movable support (not shown in Figures 3 and 4) carries the article, ythe thickness of the material of which is to be measured. In measur ing the wall thickness of tubes there suitably employed an apparatus'consisting of two rods vor tubes rigidly supported at their ends, `and two `tables arranged at the ends of the rods or tubes. The tubes, the wall thickness of which is to be measured, are placed on one of these tables. After measuring has been performed, the tubes are Vsuccessively transferred lto the other table.

Diierent types of indicating instruments or indicatordevices may, of course, he used, and similarly the motion transmission device for the same may be varied. Instead of the 'instrument being arranged for direct reading, vpreviously known devices for continuous registering oi diaF grams or for ihm-photographic exposure of the measuring result may be employed. Further.- more, the wires 4 together with the indicating instrument may, of course, be movable .so as to be capable oi 'being displaced in relation to .the article, the thickness of the ,material of which is to be measured, which article in that .case may be supported stationarily.

Figures .5 and 6 show .an embodiment which `.broadly .speaking corresponds to the embodiment according to Figures 3 and 4. The Vdifference .between these two embodiments .consists ,esserttially therein that, according to Figures -5 yand f,

lthe feelers are movable ,parallellyalong the wires,

whereas both the wires 4 and the article, :the thickness of the material of which is to be measured, are stationary. For this purpose, the sleeves I5 are not clamped on the wires y4, .but are slidable thereon and rigidly connected to wires -23 which are slidably guided -in longitudinal grooves 24 provided in the wires 4. Further, the indicating instrument 2i) is carried in apara- -lelogram like manner by links `25 which-arepiyot ally'conn-ected .to cross-pieces .21E secured to .the wires 23. participate in the travelling movement of the feelers which may be effected vby means of suitable devices V(not shown). As a matter of fact. 'the operation corresponds to that stated in conjunction with the .description of Figures :3 .and 4,

Thus, the indicating instrument Awill Ill() T6 andhcnce afdescription therecf'may be :dispensed with.

According to .the embodiment shown in Figures 7c to 11. which mainly is .adapted for measuring -lthe wall thickness Zof great tube lengths, the aplparatus is supported bystrong bed pillars 3l, on which a track formed by a pair .of parallel rods `32 rests. .Fixed under tension 'between thezoute'r- :most bed pillars is a strong vsteel 'wire 3-3 parallel to the track, .or the like. The tension .of 4the steel `wire may be regulated in 1a suitable manner, and Aone end ofthe .same `is `conveniently detachable Vsothat ltherwir'e may be introduced into the tube, the ywall thickness Vof which is 'to be measured. Approximately in the vmiddle of the steel wire there. is provided an :electric `.contact .34 which 4may :be :adjustable along the wire. .Disposed .on the track formed by `the rods 32 lis an elongated pipe supporting'carriage mounted on rollers .35 running Yon'the rods. tThezcarriage consists .of 1a .number .of crossepieces 36 .(see Figure 99, on the y.ends A,of 4which "the vro'llsr35 :are .journalled The 4cross-:pieces are interconnected by means of a commonbar 31 which Vpasses through vcollars 36a fon the cross-pieces, which latter maybe 'adjusted along the ybar 3l. From the'sleeves 35a Aextend liarrns .3 8 which in turn are provided with sleeves 38a (see Figure il), in which a shaft 39 is 'ro- Atatively mounted. -Onfthesleeves 38a there yare frotativelyfmounted auxiliary Yarms `41B situated in :close proximity `to the arms 38, which :arms '4D may thus -be adiusted angularly around the shaft .39. jThe adjustment :may :be regulated by means vof set screws 4f! I(see Figure 10) which are threaded through projections 42 on auxiliary collars `:12a which are spline guided von the ,shaft :39, inasmuch as splines secured to the collars extend finto la longitudinal groove in fthe shaft l(see Figure 1:09.. 'The auxiliary collars 42a are 'connected to the arms v313 by means .of annular `flanges 42e entering into annular grooves 'provided in the vsleeves 38a (see Figure 11:). The set screws 4| cooperate with projections 4-2b on athe .arms :49. The free ends of the auxiliary 4arms 40 project into openings 143 in sliding pins 44 which are guided :in heads 45 on the free :ends of the arms .38. The upper ends of the pins 44 ar-.e in the ,form of V-shaped holders 46 adapted to `carry the tube a, (see Figures 9 and .103..

Secured :to the shaft 39, Figs. 8a and `9, is 'a further farm 48, on which is movably disposed va counterweight T49 Vwhich may be adjusted `along the arm by the Iaid of ascrew 59 threaded .through a projection 151 on the counterweight 49.

'.By the adjustment of the arms 4I) theholders 46 may .be adjusted in such a Amanner Athat the tube a `will rest loosely inail of the holders ,independently of its longitudinal prole, while at the same time a generatrix of the tube wall, located at :the lower side, becomes as much as possible parallel to the steel wire .33.

After Kthis vadjustment has been carried out, the 4.counterweight 49 is :set Yin such a position 'that-the tube exerts only'a slight pressure against a measuring instrument more particularly indicated `in the following.

The carriagev may .be moved along the track by means of an endless krope v52-passed .overrope pulleys 5-3 which are supported 'by .the fouter- `most bed .pillars .3|

Adjnstably mounted `on a specialbed pillar Sila, Figs. lla and 8a, located midway between lthe outermost ibed pillars, -a support 54 for ra measuring yinstrument'l which, according :to the olf on the measuring scale.

.circuit and the reading of the right'measuring value of the wall thickness of the tube is ensured.

For adjusting the micrometer screw 55, 56, to zero position it is screwed up towards the electric contact 34 so that the circuit is closed and the lamp lights and the braking action of the magnet is effective. By this a denite initial position for the measurement is obtained. Then the micrometer screw is screwed backwards, whereupon the carriage supporting the tube in the right manner in relation to the steel wire, is moved forwards to the desired point of measurement, where the micrometer screw is screwed up towards the tube which, on account of the fact lthat the counterweight 49 has previously been adjusted in a suitable manner, rests with only a slight pressure against the micrometer lscrew which thereafter is screwed upwards for raising the tube, until the contact 34 touches the inside of the tube. By this operation the circuit is closed across the tube, and the lamp ignites, besides which the adjusting movement of the micrometer screw is automatically braked by the magnetic brake 51. The wall thickness of the tube at this point may be directly read on the scale of the micrometer screw. After the micrometer screw has been screwed backwards and the carriage has been displaced, the wall thickness may, in a corresponding manner, be read off concerning any other point of the tube.

According to the embodiment last described it is assumed that the tube or article a, the thickness of the material of which is to be measured, consists f current-conducting material. However, this is not necessary if the contact device and the current conductors are modified in a suitable manner. An embodiment thereof is shown in Figures l2 and 13. .According to this example, in the wire 33 there is provided a longitudinal groove for the reception ofga small wire 5t which is electrically insulated from the wire 33 in a suitable manner. The wire 6G is connected to a ring clamp 6|, or the like, located on the wire l33 and electrically insulated from this latter, which clamp is provided with a contact $52. Fastened to the wire 33 is another electrically insulated ring clamp 63 or the like, provided with a contact spring 64 which normally occupies contact break position relatively to the contact 62. The wires 33 and B are interconnected via a current source, and included in the circuit is moreover an acoustic or light signalling device which operates when the circuit is closed. As previously stated, the circuit also includes a magnetic brake such as 51, for automatic braking of the micrometer screw. When upon the adjustment of the micrometer screw the tube actuates the contact spring 54, and the latter is caused to touch the contact 62, the circuit is closed and the signalling device operates to indicate that the wall thickness has been measured so that such thickness can be read At the same time the micrometer screw is automatically braked and locked by the magnetic brake so that overadjustment is avoided.

We claim:

1. An apparatus for measuring the thickness of the material of articles, such as tubes, plates or the like, particularly at points situated at comparatively great `distances'from the ends or the limiting edges of said articles, comprising a wirelike member fixed at points located at a distance from each other, means for tensioning the wirelike member, a feeling member supported by said wire-like member at a point intermediate said fixing points, a second feeling member located opposite to the first mentioned feeling member, and a measuring instrument combined with the second feeling member and adapted to indicate zero position when contact occurs between the feeling members.

2. Anapparatus for measuring the thickness of the ymaterial of articles, such as tubes, -plates or the like, particularly at points situated at comparatively great distances from the ends or the limiting edges of said articles, comprising a wirelike member xed at points located at a distance from each other, means for tensioning the wirelike member, a feeling member supported by said wire-like member at a, point intermediate said fixing points, a second feeling member located opposite to the first mentioned feeling member and a measuringinstrument combined with the second feeling member and adapted to indicate zero position when contact occurs between the feeling members, which consist of electric contacts connected to each other via a current source and adapted to effect currentclosing whenrthe point of measurement on the article is touched yby them from opposite directions.

3. An apparatus for measuring the thickness of the material of articles, such as tubes, plates or the like, particularly at points situated at comparatively great distances from the ends or the limiting edges of said articles, comprising a wirelike member xed at points located at a distance from each other, means for tensioning the wirelike member, a feeling member supported by said wire-like member at a point intermediate said fixing points, a second feeling member located opposite to the first mentioned member, a measuring instrument combined with the second feeling member and adapted to indicate zero position when contact occurs between the feeling members, which consist of electric contacts connected to each other va a current source and adapted to effect current-closing when the point of measurement on the article is touched by them from opposite directions, and an electromagnet included in the current-conducting connection between the electric contacts and adapted to serve as a magnetic brake and, at current-closing, brake or lock the measuring instrument so that the adjusting movement of the latter is automatically interrupted.

4. An apparatus for measuring the thickness of the material of articles, such as tubes, plates or the like, particularly at points situated at comparatively great distances from the ends or the limiting edges of said articles, comprising a wire-like member fixed at points located at a distance from each other, means for tensioning the wire-like member, a feeling member supported by said wire-like member at aY point intermediate said fixing points, a second feeling member located opposite to the first mentioned 9` feeling member and a measuring instrument combined with the second feeling member and adapted to indicate zero position when contact occurs between the feeling members, a track, said wire-like member being parallel to said track and a carriage movable on said track to support the tube in such a manner that an inner tube wall generatrix becomes parallel or substantially parallel to the wire-like member.

`5. An apparatus as claimed in claim 4, in lwhich the carriage supporting the tube is provided with a number of adjustable holders which carry the tube at different points along the length thereof in an adjustable manner, so that the tube, independently of its longitudinal prole, may be freely supported with an inner wall generatrix parallel or substantially parallel to the wire-like member.

6. An apparatus as claimed in claim 4, in which the carriage consists of a number of crosspieces provided with supporting rollers for engaging the track, a rod on which the cross-pieces are adjustable, arms on said cross-pieces, holders guided in said arms in such a manner that thley may be raised and lowered, auxiliary arms fof effecting raising and lowering of the holders, d auxiliary arms being operatively connected with the first-mentioned arms, and a shaft passing through all of the armsv and fixed to the auxiliary arms for actuating the latter.

BniGER uUNGs'rRM.

GUSTAF HJALMAR LARSSON.

REFERENCES CITED j-The following references are of record in the 1 ille of this patent: 

